Friday, February 26, 2016

[Botany • 2016] Rafflesia consueloae • The Smallest among Giants; A New Species (Rafflesiaceae) from Luzon Island, Philippines

Rafflesia consueloae 
  Galindon, Ong & Fernando 

Figure 2. Colour illustration of Rafflesia consueloae Galindon, Ong & Fernando based on the holotype, Fernando & Galindon 3373 (PUH).
Colour illustration by Ms Yasmin S. Ong.

A new species of Rafflesia (Rafflesiaceae) from Luzon Island, Philippines, Rafflesia consueloae Galindon, Ong & Fernando, is described and illustrated. It is distinct from all other species of Rafflesia in its small-sized flowers, the upright perigone lobes, and prominently cream-white disk surface that is often devoid of processes. Its small-sized flowers, with an average diameter of 9.73 cm when fully expanded, make it the smallest of the largest flowers in the world.

Keywords: Conservation, ecology, holoparasitic plants, taxonomy

Figure 1. Distribution of the six species of Rafflesia on Luzon Island, Philippines, including the new species, Rafflesia consueloae.
All Rafflesia images were drawn by Ms Yasmin S. Ong, five of which were originally published in David et al. (2011). Their use here is with permission of the book publisher, the Energy Development Corporation. All images are scaled relative to the actual sizes of each species.

Rafflesia R.Br. (Rafflesiaceae) is a genus of endophytic, holoparasitic plants, well-known for producing the largest flowers on record (Kuijt 1969, Meijer 1985, 1997, Nais 2001). The Philippines is one of the centers of diversity of the genus (Barcelona et al. 2009b, Pelser et al. 2013), with at least 12 species thus far recorded from the archipelago (Teschemacher 1842, Blanco 1845, Hieronymus 1885, Barcelona and Fernando 2002, Fernando and Ong 2005, Barcelona et al. 2006, 2008a, 2008b, 2009a, 2009b, 2011, 2014, Galang and Madulid 2006, Balete et al. 2010, Pelser et al. 2013), eight of which were described only since 2002. Of all known Philippine species, five are recorded from Luzon Island, viz., Rafflesia aurantia Barcelona, Co & Balete (Barcelona et al. 2009a) from Quirino Province; R. baletei Barcelona & Cajano (Barcelona et al. 2006) from Camarines Sur Province; R. lagascae Blanco (Blanco 1845, Barcelona et al. 2009, 2011 [as R. manillana Teschem.], Pelser et al. 2013) from Cagayan, Bataan, Rizal, Laguna, Quezon, and Camarines Norte Provinces; R. leonardi Barcelona & Pelser (Barcelona et al. 2008a, 2011) from Cagayan and Kalinga Provinces, and R. philippensis Blanco (Blanco 1845, Barcelona et al. 2009) [as R. banahawensis Madulid, Villariba & Agoo (2007), and as R. banahaw Barcelona, Pelser & Cajano (2007)] from Laguna and Quezon Provinces (Figure 1).

In this paper, we describe Rafflesia consueloae, the 6th species from Luzon Island, and the 13th for the entire Philippine archipelago.

Rafflesia consueloae, A few minutes after full bloom, note immaculate surface.
Photo by Biodiversity Research Laboratory, UP Biology

Figure 3. Rafflesia consueloae Galindon, Ong & Fernando.
Open flower Longitudinal section of flower showing details of ramenta Cross section through column neck showing undersurface of disk with anthers and dense fine bristles Longitudinal section of female bud showing ovary
 A–C Fernando & Galindon 3373 D Fernando & Galindon 3378 E Fernando & Galindon 3376.
All photographs by Edwino S. Fernando.

Rafflesia consueloae Galindon, Ong & Fernando, sp. nov.

Diagnosis: This species is distinct from all other Rafflesia species in its small-sized flowers (average of 9.73 cm diameter), the upright perigone lobes, and the prominently cream-white disk surface which is often devoid of processes. On Luzon Island, it overlaps in the size of mature buds and number of anthers with Rafflesia baletei and Rafflesia aurantia (Table 1).

Distribution: Endemic to the Philippines. Luzon Island, Nueva Ecija Province, Municipality of Pantabangan. The species is currently known only from two mountain sites with remnants of tropical lowland evergreen rain forests, Mt Balukbok and Mt Pantaburon, about 2 km apart, all within the Pantabangan-Carranglan Watershed.

Rafflesia consueloae population, 22 Feb 2014 [11 days after discovery].
Note the pink flags to indicate where R. consueloae in various stages of development and decay were located. Eventally more than 160 individuals were counted in this sub-site alone.

  Photo by Biodiversity Research Laboratory, UP Biology  ||

Etymology: The specific epithet honors Ms Consuelo ‘Connie’ Rufino Lopez, lifelong partner of industrialist Oscar M. Lopez, and a plant lover in her own right. Both delight in culturing, growing and tending their garden which includes more than 100 species of trees, orchids and other plants. With her demure but strong personality, traits which Rafflesia consueloae possess, she provides the inspiration for Mr Lopez’s pursuit of biodiversity conservation in the Philippines.

Conservation status: Following the IUCN Categories and Criteria (IUCN 2012), we regard this species as Critically Endangered (CR B1+2bc). The extent of occurrence of the two small populations of R. consueloae is less than 100 km2. Both populations are under the jurisdictional control of the National Irrigation Administration (NIA) and the Pantabangan-Carranglan Watershed Protected Area Management Board. The First Gen Hydro Power Corporation operates the Pantabangan hydroelectric facilities in the area and helps provide support in monitoring the surrounding forests and its biodiversity. However, the continued protection of the R. consueloae populations and other biodiversity in the area needs to be ensured as some local people still hunt wildlife there and forest fires are likely in the dry season. The vertebrate wildlife may also play a role in the biology of the R. consueloae.

How new Tetrastigma hosts get infected with Rafflesia seeds remains unknown. Several species of wildlife such as tree shrews, rodents, squirrels, wild pigs, elephants, and even ants have been suggested as potential seed dispersers of Rafflesia (Emmons et al. 1991, Hidayati et al. 2000, Nais 2001, Pelser et al. 2013); that these wildlife species might play an important role in the completion of the Rafflesia’s life cycle through the infection of new Tetrastigma hosts, had long been suspected but remains unproven. However, using motion-activated camera traps set up around fruits of R. consueloae, we were able to photograph at least two species of rodents feeding on different occasions (unpublished data, this study). What role these rodents and other wildlife species play in the life cycle of R. consueloae is subject of further study. The current two sites are known hunting grounds of wildlife by some members of the local community. Given the restricted range of this new species, hunting of wildlife might further exacerbate its fragile existence. Also, hunting might increase the chances of forest fires occurring, which are likely in the dry season based on personal observations and interviews with locals.

John Michael M. Galindon, Perry S. Ong and Edwino S. Fernando. 2016. Rafflesia consueloae (Rafflesiaceae), The Smallest among Giants; A New Species from Luzon Island, Philippines. PhytoKeys. 61: 37-46. DOI: 10.3897/phytokeys.61.7295

UP [University of the Philippines] biologists discover “the smallest among giant flowers”